Index: class-wp-screen.php
===================================================================
--- class-wp-screen.php	(revision 46561)
+++ class-wp-screen.php	(working copy)
@@ -594,8 +594,14 @@
 
 	/**
 	 * Add a help tab to the contextual help for the screen.
-	 * Call this on the load-$pagenow hook for the relevant screen.
 	 *
+	 * Call this on the load-$pagenow hook for the relevant screen,
+	 * or fetch the $current_screen object or use get_current_screen()
+	 * and then call the method from the object.
+	 *
+	 * You may need to filter $current_screen using an if or switch statement
+	 * to prevent new help tabs from being added to ALL admin screens.
+	 *
 	 * @since 3.3.0
 	 * @since 4.4.0 The `$priority` argument was added.
 	 *
@@ -603,7 +609,7 @@
 	 *     Array of arguments used to display the help tab.
 	 *
 	 *     @type string $title    Title for the tab. Default false.
-	 *     @type string $id       Tab ID. Must be HTML-safe. Default false.
+	 *     @type string $id       Tab ID. Must be HTML-safe and should be unique for this menu. It is NOT allowed to contain any empty spaces. Default false.
 	 *     @type string $content  Optional. Help tab content in plain text or HTML. Default empty string.
 	 *     @type string $callback Optional. A callback to generate the tab content. Default false.
 	 *     @type int    $priority Optional. The priority of the tab, used for ordering. Default 10.